In order to meet the high precision ground calibration and testing of sun sensor in satellite control system, a realistic simulation of solar radiation characteristic of high precision collimated solar simulator design was presented, according to the characteristics of simulator with high thermal power. The main component of the Xenon lamp in combination with the condenser lens, steering plane mirror and optical integrator was designed in detailed structure of the heat-ray control structure. Using Ansys software for thermal simulation to ensure the rationality and optimality of thermal control structure. By the actual detecting, the designed solar simulator can simulate the real characteristics of solar radiation, collimation angle is less than 32′, unevenness is better than ±1.6% when the irradiation surface is less than Φ100 mm; unevenness is better than ±4.2% when the irradiation surface is Φ(100-300) mm, meeting the high precision ground calibration and testing of sun sensor.